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 A081204 Staircase on Pascal's triangle. 3
 1, 2, 3, 10, 15, 56, 84, 330, 495, 2002, 3003, 12376, 18564, 77520, 116280, 490314, 735471, 3124550, 4686825, 20030010, 30045015, 129024480, 193536720, 834451800, 1251677700, 5414950296, 8122425444, 35240152720, 52860229080, 229911617056 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS Arrange Pascal's triangle as a square array. This sequence is then a diagonal staircase on the square array. LINKS Vincenzo Librandi, Table of n, a(n) for n = 0..200 FORMULA a(n) = binomial(ceiling((n)/2) + n, n). a(n) = Sum_{k=0..floor(n/2)} binomial(n+k-1, k). - Paul Barry, Jul 06 2004 Conjecture: 4*n*(n+1)*(6*n^2 - 15*n + 8)*a(n) + 6*n*(9*n-7)*a(n-1) - 3*(3*n-4)*(3*n-2)*(6*n^2-3*n-1)*a(n-2) = 0. - R. J. Mathar, Nov 07 2014 Conjecture: 8*n^2*(n+1)*a(n) - 12*n*(83*n^2 - 313*n + 232)*a(n-1) + 6*(-9*n^3 - 377*n + 384)*a(n-2) + 9*(3*n-5)*(83*n-64)*(3*n-7)*a(n-3) = 0. - R. J. Mathar, Nov 07 2014 MATHEMATICA Table[Binomial[Ceiling[(n)/2] + n, n], {n, 0, 30}] (* Vincenzo Librandi, Aug 07 2013 *) PROG (MAGMA) [Binomial(Ceiling((n)/2) + n, n): n in [0..30]]; // Vincenzo Librandi, Aug 07 2013 CROSSREFS Cf. A065942, A081181, A081205. Sequence in context: A226881 A026336 A027913 * A293308 A106672 A069156 Adjacent sequences:  A081201 A081202 A081203 * A081205 A081206 A081207 KEYWORD easy,nonn AUTHOR Paul Barry, Mar 11 2003 STATUS approved

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Last modified December 15 00:30 EST 2019. Contains 329988 sequences. (Running on oeis4.)